不同温度条件下CO_2水溶液对碳酸盐岩的溶蚀作用

Dissolution of Carbonate Rocks in CO_2 Solution under the Different Temperatures

普遍认为酸性流体的溶蚀作用是碳酸盐岩储层形成的重要制约因素。本文以一个全新的模拟实验方式对不同类型碳酸盐岩在CO2水溶液中的相对溶蚀能力进行了研究，结果发现随温度从常温至200℃，碳酸盐岩的溶蚀能力由弱变强再变弱，在60—90℃区间内溶蚀能力最强。白云岩不管在低温还在高温环境下，总比灰岩更难溶蚀，过渡类型的岩类介于二者之间，当温度大于150℃后，CO2对碳酸盐岩的溶蚀能力变得越来越弱。灰岩与白云岩的溶蚀差异也变得越来越小。这暗示碳酸盐岩在早成岩晚期一中成岩早期，CO2水溶液对灰岩的溶蚀作用有重要影响，而对白云岩的溶蚀作用影响较小，白云岩优质储层的形成可能与碳酸盐岩中钙质的流失或白云岩化作用有关。

It is thought generally that dissolution of acidic fluids is an important controlling factor for forming carbonate reservoir. This study focuses on the ability of dissolution of different type carbonate rocks in CO2 solution using a new simulating experiment way. The results show that the ability of dissolution of different carbonate rocks changes from low to high and again to lower with the simulating temperature from 25℃ to 200℃ ,and the maximum ability of dissolution is at 60 -90℃ ; the ability of dissolution of dolomite is lower compared with the ability of dissolution of calcite, and the ability of dissolution of transitional type carbonate rocks is between calcite＇ s and dolomite＇ s, and the ability of dissolution is very lower and their different is very small for all type carbonate rocks in CO2 solution when the simulating temperature is higher than 150℃. This indicates that CO2 solution has important effect on dissolution of limestone and less effect on dissolution of dolomite during late stage of early diagenetic to early stage of middle diagenetic and the forming of good dolomite reservoir is related to dolomitization.